Low density lipoprotein/fibrinogen adsorbent and adsorption apparatus capable of whole blood treatment

ABSTRACT

The present invention provides an adsorbent, an adsorption method, and an adsorber for efficiently adsorbing low-density lipoproteins and fibrinogen directly from a body fluid, particularly whole blood, to decrease the concentrations of these components in the body fluid with minimizing losses of useful substances such as HDL and albumin. The adsorbent includes a tryptophan derivative and a polyanionic compound which are immobilized on a water-insoluble porous carrier, wherein the amount of the immobilized polyanionic compound is 0.10 μmol to 1.5 μmol per milliliter of wet volume of the adsorbent, and the molar ratio of the amount of the immobilized tryptophan derivative to the amount of the immobilized polyanionic compound is 1 to 70. The adsorbent is capable of whole blood treatment for safely and efficiently adsorbing low-density lipoproteins and fibrinogen.

TECHNICAL FIELD

The present invention relates to an adsorbent for adsorbing low-densitylipoproteins and fibrinogen present in a body fluid to decrease theconcentrations thereof in the body fluid. Also, the-present inventionrelates to a method for removing low-density lipoproteins and fibrinogenfrom a body fluid by adsorption on the adsorbent. Furthermore, thepresent invention relates to an adsorber using the adsorbent forlow-density lipoproteins and fibrinogen in a body fluid. Particularly,the present invention relates to an adsorbent capable of whole bloodtreatment.

BACKGROUND ART

In recent years, patients affected by arteriosclerosis have increased innumber with westernization of eating habits and aging. It is well knownthat low-density lipoproteins (LDL) and very low-density lipoproteins(VLDL) are rich in cholesterol and thus cause arteriosclerosis. It isalso the fact that arteriosclerosis highly develops in patients withhyperlipemia or hypercholesterolemia. On the other hand, high-densitylipoproteins (HDL) are known as a retardation factor againstarteriosclerosis.

Although therapies for these diseases include a dietary therapy and adrug therapy, a therapy applied to a patient who cannot be effectivelytreated by these therapies comprises extracorporeally removinglow-density lipoproteins from the blood by adsorption. In particular, atherapy of perfusing the blood plasma separated from the blood throughan adsorber filled with an adsorbent comprising cellulose beads withimmobilized dextran sulfate to remove the low-density lipoproteins iswidely used with a high curative effect.

On the other hand, it has been reported that a fibrinogen concentrationis correlated with the incidence of coronary artery diseases andcerebral apoplexy (W. B. Kannel et al., The Journal of the AmericanMedical Association, Vol. 258, pp. 1183-1186, 1987). In order to preventthe occurrence of these diseases related to arteriosclerosis, it isdesired to decrease the fibrinogen concentration as well as theconcentration of low-density lipoproteins.

In particular, arteriosclerosis causing the occlusion of a peripheralblood vessel is referred to as “arteriosclerosis obliterans”. In thisdisease, the peripheral blood vessel is narrowed or occluded to worsenthe circulation of peripheral blood, thereby causing symptoms such ascoldness in the limbs, numbness, intermittent claudication, a pain atrest, an ulcer, mortification, and the like, leading to limb amputation.It has been also reported that a patient with the arteriosclerosisobliterans having such lesions in the peripheral blood vessel has ahigher fibrinogen concentration than that of a healthy adult (P. Poredoset al., Angiology, Vol. 47, No. 3, pp. 253-259, 1996). In treatment ofthe arteriosclerosis obliterans, therefore, it is also desired todecrease the fibrinogen concentration as well as the concentration oflow-density lipoproteins.

As described above, a therapy desired for a patient witharteriosclerosis, particularly arteriosclerosis obliterans, comprisesdecreasing the concentrations of low-density lipoproteins and fibrinogenin blood. The above-described therapy of removing the low-densitylipoproteins from blood plasma by adsorption on the adsorbent comprisingcellulose beads with immobilized dextran sulfate is excellent inadsorption of the low-density lipoproteins, but the therapy is notnecessarily sufficient for decreasing the fibrinogen concentration. Insome cases, double filtration plasmapheresis is applied. In this method,the plasma separated by a plasma separator is introduced into a plasmafilter membrane to remove an unfiltered substance, i.e., a substancelarger than the pore diameter of the membrane, together with water. Thismethod can securely remove low-density lipoproteins and fibrinogen, butit is disadvantageous in that the filtration system used requireselectrolytic transfusion (fluid replacement), and even if a complicatedoperation such as temperature control, recirculation, or the like isperformed, selectivity for a substance to be removed is lower than thatof adsorption, thereby removing useful substances other than low-densitylipoproteins and fibrinogen, for example, albumin, immunoglobulin suchas IgG, HDL-cholesterol, and the like (Yoshie Konno, et al., JapaneseJournal of Apheresis, Vo. 22, No. 1, pp. 44-50, 2003). Furthermore, ithas been reported that a therapy referred to as a “heparin precipitationmethod” has been developed for removing low-density lipoproteins andfibrinogen. However, this method comprises a complicated operation andis not popularized as a general therapy.

Also, it is known that fibrinogen and low-density lipoproteins can beremoved with an adsorbent comprising a cross-linked porous materialcontaining a compound in its surfaces, the compound having a hydrophobicstructure and an anionic functional group (Japanese Unexamined PatentApplication Publication No. 7-136256). Although the adsorbent hasexcellent adsorption ability for fibrinogen, the adsorption ability forlow-density lipoproteins is not sufficient. In order to exhibit theclinically sufficient adsorption ability of the adsorbent, a largeamount of the adsorbent must be used. Therefore, the amount of the bloodtaken out from a body in a therapy is increased to increase theprobability of occurrence of a blood pressure drop in the therapy. Thisdocument also discloses a preferred method for using the adsorbent inwhich plasma is separated from blood by a plasma separator and thentreated from the viewpoint of influences on blood cell components suchas platelets.

Therefore, the conventional methods for decreasing the low-densitylipoproteins and fibrinogen are disadvantageous in that the methodscomprise complicated operations due to a plasma separation system andhave low performance, and useful substances are also removed. On theother hand, a system for direct whole blood treatment without plasmaseparation from blood has recently attracted attention as anextracorporeal circulation therapy using an adsorbent in view ofsimplicity of operations and shortening of the therapy time. The directwhole blood treatment system does not require plasma separation using aplasma separator or the like, and is capable of direct treatment of theblood anticoagulated with an anticoagulant. Therefore, the circuit isvery simple, and the target substance can be effectively adsorbed withina short time. Consequently, a decrease in burden to a patient andmedical staff is expected.

However, the direct whole blood treatment system is required to decreasethe interaction between the adsorbent and blood cells and decrease theinfluence on the blood cell components as much as possible. In thedirect whole blood treatment, it is most important to inhibit theactivation of leukocytes and platelets as much as possible. When theactivation is low, a loss of these blood cells can be prevented.Particularly, when a blood vessel is damaged, the platelets adhere tothe damaged site, and a fibrinogen receptor is expressed on the surfaceto form thrombus due to cross-linking of the platelets with fibrinogen.The thrombus possibly covers the damaged site to prevent a bloodleakage. Therefore, the technique for adsorbing fibrinogen by wholeblood treatment is considered very difficult. With respect to theabove-described adsorbent comprising a cross-linked porous materialcontaining a compound in its surfaces, the compound having a hydrophobicstructure and an anionic functional group, there is no concrete study ofa method of direct whole blood treatment, and a plasma treatment systemis considered preferable (Japanese Unexamined Patent ApplicationPublication No. 7-136256).

As described above, there has been no conventional method foreffectively removing low-density lipoproteins and fibrinogen by a verysimple operation of whole blood treatment without plasma separation anda loss of other useful substances. Therefore, the development of such amethod has been demanded.

DISCLOSURE OF THE INVENTION

In order to solve the above problems, the present invention provides anadsorbent for efficiently adsorbing low-density lipoproteins andfibrinogen from a body fluid, particularly whole blood, to decrease theconcentrations of the low-density lipoproteins and fibrinogen in thebody fluid while minimizing a loss of useful substances such as albuminand HDL. The present invention also provides a method for adsorbinglow-density lipoproteins and fibrinogen in a body fluid using theadsorbent. The present invention further provides an adsorber comprisingthe adsorbent for adsorbing low-density lipoproteins and fibrinogen in abody fluid. Particularly, the present invention provides an adsorbentand adsorber capable of minimizing a loss of blood cells and safelytreating whole blood.

The inventors carried out intensive research of an adsorbent capable ofminimizing a loss of useful substances such as albumin and HDL andeffectively adsorbing low-density lipoproteins and fibrinogen by wholeblood treatment. As a result, the inventors found an adsorbentcomprising a tryptophan derivative and a polyanionic compound which areimmobilized on a water-insoluble porous carrier, wherein a predeterminedamount of the polyanionic compound is immobilized, and the molar ratioof the amount of the immobilized tryptophan to the amount of theimmobilized polyanionic compound is in a specified range. Also,inventors found that the adsorbent is capable of safe whole bloodtreatment for effectively adsorbing low-density lipoproteins andfibrinogen in a body fluid while minimizing a loss of blood cells. Thisfinding resulted in the achievement of the present invention.

In a first aspect of the present invention, an adsorbent capable ofwhole blood treatment for adsorbing low-density lipoproteins andfibrinogen comprises a tryptophan derivative and a polyanionic compoundwhich are immobilized on a water-insoluble porous carrier, wherein theamount of the immobilized polyanionic compound is 0.10 μmol to 1.5 μmolper milliliter of wet volume of the adsorbent, and the molar ratio ofthe amount of the immobilized tryptophan derivative to the amount of theimmobilized polyanionic compound per milliliter of wet volume of theadsorbent is 1 to 70. In a second aspect of the present invention, amethod for adsorbing low-density lipoproteins and fibrinogen comprisesbringing the adsorbent into contact with a body fluid containing thelow-density lipoproteins and fibrinogen. In a third aspect of thepresent invention, an adsorber capable of whole blood treatment forabsorbing low-density lipoproteins and fibrinogen comprises a containerhaving a fluid inlet and outlet and a means for preventing an outflow ofthe adsorbent to the outside, the container being filled with theadsorbent for low-density lipoproteins and fibrinogen.

In the present invention, the term “body fluid” means blood or plasma.

In the present invention, the term “polyanionic compound” means acompound having a plurality of anionic functional groups in itsmolecule. In the present invention, examples of the anionic functionalgroups include functional groups negatively charged at neutral pH, suchas a carboxyl group, a sulfonate group, a sulfate group, and a phosphategroup. Among these functional groups, from the viewpoint of adsorptionability, a carboxyl group, a sulfonate group, and a sulfate group arepreferred. In view of highest adsorption ability, a sulfate group isparticularly preferred.

Representative examples of the polyanionic compound include syntheticpolyanionic compounds such as polyacrylic acid, polyvinylsulfonic acid,polystyrenesulfonic acid, polyglutamic acid, polyasparaginic acid,polymethacrylic acid, polyphosphoric acid, and styrene-maleic acidcopolymers; synthetic acid polysaccharides such as dextran sulfate andcarboxymethyl cellulose; acid tissue-derived acid mucopolysaccharideshaving sulfate groups, such as chondroitin sulfate, dermantan sulfate,and keratan sulfate; acid mucopolysaccharides having N-sulfonate groupsor sulfate groups, such as heparin and heparan sulfate; tissue-derivedpolysaccharides having anionic functional groups, such as chondroitinand phosphomannan; and tissue-derived nucleic acids such asdeoxyribonucleic acid and ribonucleic acid. However, the polyanioniccompound is not limited to these representative examples.

Among these representative compounds, it is practical to use syntheticcompounds rather than directly using tissue-derived compounds because ahigh-purity substance can be obtained at low cost, and the amount of theanionic functional groups introduced can be controlled. From theseviewpoints, synthetic polyanionic compounds such as polyacrylic acid,polyvinylsulfuric acid, polyvinylsulfonic acid, polystyrenesulfonicacid, polyglutamic acid, polyasparaginic acid, polymethacrylic acid,polyphosphoric acid, and styrene-maleic acid copolymers; and syntheticacid polysaccharides such as dextran sulfate and carboxymethyl celluloseare preferably used. In particular, from the viewpoint of low cost,polyacrylic acid, polystyrenesulfonic acid, and dextran sulfate are morepreferred, and dextran sulfate is most preferred from the viewpoint ofsafety.

The molecular weight of the polyanionic compound is preferably 1000 ormore, and more preferably 3000 or more in view of affinity for thelow-density lipoproteins and the fibrinogen adsorbing ability incombination with tryptophan. Although the upper limit of the molecularweight of the polyanionic compound is not particularly limited, theupper limit is preferably 1,000,000 or less from the practicalviewpoint.

In the present invention, any one of various methods for immobilizingthe polyanionic compound to the water-insoluble porous carrier may beused. Representative examples of the method include (1) a graftingmethod using radiation or electron beams for covalently bonding thepolyanionic compound to the surfaces of the water-insoluble porouscarrier, and (2) a chemical method of covalently bonding the polyanioniccompound through the functional groups of the water-soluble porouscarrier.

In the present invention, in view of the structure of the adsorbent inwhich the polyanionic compound and the tryptophan derivative areimmobilized, the chemical method of covalently bonding the polyanioniccompound through the functional groups is simpler and preferred becausethe tryptophan derivative can be immobilized by the same method.

In the present invention, examples of the tryptophan derivative includetryptophan, tryptophan esters such as tryptophan ethyl ester andtryptophan methyl ester, and compounds having indole rings andstructures similar to tryptophan, such as tryptamine and tryptophanol.The tryptophan derivative may be an L-isomer, a D-isomer, a DL-isomer,or a mixture thereof. Alternatively, a mixture of at least twotryptophan derivatives may be used. Among these tryptophan derivatives,tryptophan is preferred from the viewpoint of safety, and L-tryptophanis most preferable in practical use because safety data is abundant, andtryptophan is a natural amino acid, most inexpensive, and readilyavailable.

In the present invention, as the method for immobilizing the tryptophanderivative, the chemical method of covalently boding the tryptophanderivative through the functional groups of the water-insoluble porouscarrier is preferably used.

In the present invention, the amount of the immobilized polyanioniccompound must be 0.10 μmol to 1.5 μmol per milliliter of wet volume ofthe adsorbent, and the molar ratio of the amount of the immobilizedtryptophan derivative to the amount of the immobilized polyanioniccompound must be 1 to 70.

In the present invention, the molar ratio (TR/PA ratio) of the amount ofthe immobilized tryptophan derivative to the amount of the immobilizedpolyanionic compound is calculated according to the following equation:TR/PA ratio=molar number of the immobilizedtryptophan derivative per milliliter of wet volume of theadsorbent/molar number of the immobilized polyanionic compound permilliliter of wet volume of the adsorbent.

The inventors carried out intensive study on the amount of theimmobilized polyanionic compound, the amount of the immobilizedtryptophan derivative, low-density lipoproteins and fibrinogen, andblood cell passing property in direct whole blood treatment. As aresult, it was surprisingly found that when the amount of theimmobilized polyanionic compound is controlled to 0.10 μmol to 1.5 μmolper milliliter of wet volume of the adsorbent, and the molar ratio TR/PAis controlled to 1 to 70, high adsorption ability is exhibited for thelow-density lipoproteins and fibrinogen, and passing property toleukocytes and platelets is excellent.

In the present invention, the amount of the immobilized polyanioniccompound is 0.10 μmol to 1.5 μmol per milliliter (wet volume) of theadsorbent. With the amount of less than 0.10 μmol, the passing propertyto leukocytes and platelets is low to decrease the number of theleukocytes in the pooled blood in whole blood perfusion. With the amountof over 1.5 μmol, the fibrinogen adsorbing ability is less exhibitedeven when the tryptophan derivative is immobilized. In view of highblood cell passing property and high adsorption ability, the amount ofthe immobilized polyanionic compound is preferably 0.12 μmol to 1.0μmol, and more preferably 0.15 μmol to 0.50 μmol.

In the present invention, the molar ratio (TR/PA ratio) of the amount ofthe immobilized tryptophan derivative to the amount of the immobilizedpolyanionic compound is 1 to 70. With the TR/PA ratio of less than 1,the fibrinogen adsorbing ability of the tryptophan derivative is lessexhibited. Conversely, with the TR/PA ratio over 70, the passingproperty to leukocytes and platelets gradually worsens to decrease thenumber of the leukocytes in the pooled blood in whole blood perfusion.In view of high blood cell passing property and high adsorption ability,the molar ratio is preferably 5 to 60, and more preferably 10 to 50.

In the present invention, the wet volume of the adsorbent is determinedas follows: The adsorbent is immersed in water and transferred as slurryinto a measuring container such as a measuring cylinder, and theadsorbent slurry is spontaneously settled in the measuring container.Then, a rubber mat is placed for preventing breakage of the measuringcontainer, and the measuring container is gently dropped about 5 to 10times onto the mat from a height of about 5 to 10 cm in the verticaldirection (so that the settled adsorbent does not extremely rise) toapply vibration to the adsorbent. After the measuring container isallowed to stand for 15 minutes or more, the volume of the adsorbentsettled is measured. The operation of vibration and standing isrepeated, and the volume of the adsorbent settled is measured as the wetvolume when the volume of the adsorbent settled is not changed.

In the present invention, examples of the method for measuring theamount of the immobilized polyanionic compound include a method ofdetermining the content of an element in the polyanionic compound in theadsorbent (for example, when dextran sulfate is the polyanioniccompound, the sulfur content in the adsorbent is determined), and amethod of measuring a decrease in amount of a pigment in a pigmentsolution in contact with the adsorbent, the pigment having the propertyof bonding to the polyanionic compound. Among these methods, the methodusing the pigment solution is capable of simply and precisely measuringthe amount of the immobilized polyanionic compound. The method will bedescribed in detail below in EXAMPLE 1. When the polyanionic compound isdextran sulfate or polyacrylic acid, the amount of the immobilizedcompound can be simply measured from the amount of the toluidine blueadsorbed on the adsorbent in contact with a toluidine blue solutionbecause the compound has the property of bonding to the toluidine blue.

In the present invention, the amount of the immobilized tryptophanderivative can be determined by using the property that a color isgenerated when an aldehyde such as p-dimethylbenzaldehyde is condensedwith the indole ring in the molecule of the tryptophan derivative undera strong acid condition (Amino Acid Fermentation (second volume) editedby Koichi Yamada, pp. 43-45, Kyoritsu Shupppan, 1972). The amount of theimmobilized tryptophan derivative can also be determined by a methodusing the property that fluorescent light with a peak at about 350 nm isemitted when the indole ring in the molecule of the tryptophanderivative is excited with light at about 280 nm. When the carriercomprises a compound not containing nitrogen, the amount can be measuredby determining the nitrogen content in the adsorbent, as will bedescried in detail below in the method of EXAMPLE 1.

In the present invention, the water-insoluble porous carrier iswater-insoluble at normal temperature and normal pressure, and has fineholes of an appropriate size, i.e., a porous structure. As the shape ofthe water-insoluble porous carrier, any one of a spherical shape, agranular shape, a flat membrane, a fibrous shape, a hollow fiber, andthe like may be effectively used. However, a spherical shape or agranular shape is preferably used from the viewpoint of ease ofhandling.

When the water-insoluble porous carrier has a spherical shape orgranular shape, the average particle size of the carrier is preferablyas large as possible in view of the point that the adsorbent of thepresent invention is capable of whole blood treatment. However, in viewof adsorption efficiency, the average particle size is preferably assmall as possible. In the present invention, in order to permit thewhole blood treatment and the exhibition of high adsorption efficiency,the average particle size of the adsorbent is preferably 100 μm to 1000μm. Also, from the viewpoint that high blood cell passing property andadsorption efficiency can be exhibited, the average particle size of theadsorbent is more preferably 200 μm to 800 μm, and most preferably 400μm to 600 μm.

The water-insoluble porous carrier preferably has a molecular weightexclusion limit of 5×10⁵ or more for globular proteins. As described ina book (Size Exclusion Chromatography, written by Sadao Mori, KyoritsuShuppan), the molecule weight exclusion limit means the molecular weightof a molecule having the smallest molecular weight among the moleculesnot entering in fine pores (excluded) when a sample having variousmolecular weights is flowed in size exclusion chromatography. When themolecular weight exclusion limit for globular proteins is less than5×10⁵, it is not practical because of the low adsorption ability forfibrinogen and low-density lipoproteins. When the molecular weightexclusion limit for globular proteins is over 1×10⁸, the pore size isexcessively large to decrease the surface area contributing toadsorption, thereby decreasing the adsorption ability for fibrinogen andlow-density lipoproteins. In the present invention, therefore, themolecular weight exclusion limit of the water-soluble porous carrier forglobular proteins is preferably 5×10⁵ to 1×10⁸, and more preferably1×10⁶ to 1×10⁸, and most preferably 2×10⁶ to 1×10⁸ from the viewpoint ofexhibition of adsorption ability.

In the present invention, the water-insoluble porous carrier preferablyhas functional groups usable for bonding for immobilizing thepolyanionic compound and the tryptophan derivative. Representativeexamples of the functional groups include an amino group, an amidegroup, a carboxyl group, an acid anhydride group, a succinimide group, ahydroxyl group, a thiol group, an aldehyde group, a halogen group, anepoxy group, a silanol group, and a tresyl group. However, thefunctional groups are not limited to these groups. The water-insolubleporous carrier may be activated by a method, for example, ahalogenation-cyanidation method, an epichlorohydrin method, a bisepoxidemethod, or a bromoacetyl bromide method. Among these methods, theepichlorohydrin method is most preferably used from the viewpoint ofpractical use and safety.

In the present invention, it is undesirable that the water-insolubleporous carrier is excessively soft or easily broken. When consolidationoccurs during flowing of a body fluid, a sufficient flow rate of thebody fluid cannot be obtained to extend the treatment time and fail tocontinue the treatment. Therefore, in order to prevent the consolidationof the adsorbent, the adsorbent preferably has sufficient mechanicalstrength (hardness). The term “hardness” means that when an aqueousliquid is flowed through a cylindrical column uniformly filled with theadsorbent, the pressure drop and the flow rate have a linearrelationship up to at least 0.3 kgf/cm², as shown below in a referenceexample.

In the present invention, the material of the water-insoluble porouscarrier is not particularly limited. However, representative examples ofthe material include organic carriers comprising polysaccharides, suchas cellulose, cellulose acetate, and dextrin; synthetic polymers such aspolystyrene, styrene-divinylbenzene copolymers, polyacrylamide,polyacrylic acid, polymethacrylic acid, polyacrylic acid esters,polymethacrylic acid esters, and polyvinyl alcohol. The water-insolubleporous carrier may have a coating layer comprising a polymer materialhaving a hydroxyl group, such as a polymer of hydroxyethyl methacrylate,a graft copolymer such as a copolymer of a monomer having a polyethyleneoxide chain with another polymerizable monomer, or the like. Among thesematerials, cellulose or a synthetic polymer such as polyvinyl alcohol ispreferably used for practical use because active groups can easily beintroduced into the carrier surfaces.

Among these materials, the cellulose carrier is most preferably used.The cellulose carrier has the advantages: (1) It is hardly broken orcauses fine particles because of its relatively high mechanical strengthand toughness, and thus even if the body fluid is flowed through acolumn filled with the cellulose carrier at a high flow rate,consolidation little occurs to permit the body fluid to flow at a highspeed. (2) It has high safety as compared with a synthetic polymercarrier. Therefore, the cellulose carrier is most preferably used as thewater-insoluble porous carrier in the present invention.

As an anticoagulant for an extracorporeal circulation therapy using anadsorber of the present invention, any one of heparin, low-molecularweight heparin, nafamostat mesilate, gabexate mesilate, argatroban, asodium citrate solution, and a citric acid-containing anticoagulant suchas an acid citrate-dextrose solution (ACD solution) and acitrate-phosphate-dextrose solution (CPD solution) may be used. Inparticular, from the viewpoint of whole blood treatment, a citricacid-containing anticoagulant, heparin, low-molecular weight heparin, ornafamostat mesilate is particularly preferably used as theanticoagulant.

There are various methods for adsorbing the low-density lipoproteins andfibrinogen from the body fluid using the adsorbent of the presentinvention. Representative examples of the methods include a methodcomprising taking out the body fluid and storing it in a bag or thelike, mixing the adsorbent with the body fluid to remove the low-densitylipoproteins and fibrinogen, and then filtering off the adsorbent toobtain the body fluid free from the low-density lipoproteins andfibrinogen, and a method comprising preparing an adsorber comprising acontainer which is filled with the adsorbent and which has a body fluidinlet and outlet, the outlet having a filter for passing the body fluidbut not passing the adsorbent, and flowing the body fluid through theadsorber. Either of the methods may be used, but the latter methodcomprises a simple operation and can be incorporated into anextracorporeal circulation circuit to permit the on-line efficientremoval of the low-density lipoproteins and fibrinogen from the bodyfluid of a patient. Therefore, this method is most preferred as themethod for adsorbing the low-density lipoproteins and fibrinogen usingthe adsorbent of the present invention.

The adsorber of the present invention comprises a container which isfilled with the adsorbent and which has a body fluid inlet and outlet,the outlet having a filter for passing the body fluid but not passingthe adsorbent. The capacity of the adsorber of the present inventionmust be 100 ml or more from the viewpoint of the effect of decreasingthe low-density lipoproteins and fibrinogen. Although the capacity ofthe adsorber is not limited from the viewpoint of adsorption ability,the capacity of the adsorber is preferably 1000 ml or less, and morepreferably 800 ml or less, because a blood pressure drop possibly occurswhen the amount of the blood taken out from the body is excessivelylarge. The capacity of the adsorber is most preferably 400 ml or lessfrom the viewpoint that even if the adsorber is incorporated into thecircuit of another blood purification therapy such as hemodialysis orthe like, the amount of the blood extracorporeally circulated is notexcessively increased, and a blood pressure drop possibly occurring whenblood is taken out from the body can be prevented as much as possible.

The adsorber of the present invention will be described with referenceto FIG. 1 which is a schematic cross-sectional view of an example.

In FIG. 1, reference numeral 1 denotes a fluid inlet, reference numeral2 denotes a fluid outlet, reference numeral 3 denotes an adsorbent forlow-density lipoproteins and fibrinogen, reference numerals 4 and 5 eachdenote a mesh, reference numeral 6 denotes a column, and referencenumeral 7 denotes an adsorber for low-density lipoproteins andfibrinogen. However, the adsorber for low-density lipoproteins andfibrinogen of the present invention is not limited to this example, andthe shape of the adsorber is not particularly limited as long as itcomprises a container filled with the adsorbent for low-densitylipoproteins and fibrinogen, the container having a fluid inlet andoutlet and means for preventing an outflow of the adsorbent to theoutside.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail below with referenceto examples.

REFERENCE EXAMPLE

A glass cylindrical column (inner diameter: 9 mm, column length: 150 mm)comprising filters (pore size: 15 μm) provided at both ends wasuniformly filled with each of an agarose material (Biogel A-5m producedby Bio-Rad Laboratories, Inc., particle diameter: 50 to 100 mesh), avinyl polymer material (Toyopearl HW-65 produced by Tosoh Corporation,particle diameter: 50 to 100 μm), and a cellulose material (CellulofineGC-700m produced by Chisso Corporation, particle diameter: 45 to 105μm). Then, water was flowed through the column by a peristaltic pump todetermine the relation between the flow rate and pressure drop ΔP. Theresults are shown in FIG. 2.

FIG. 2 shows that with Toyopearl HW-65 and Cellulofine GC-700m, the flowrate increases substantially in proportion to increases in pressure,while with BiogelA-5m, the flow rate does not increase due toconsolidation even when the pressure is increased. In the presentinvention, like Toyopearl HW-65 and Cellulofine GC-700m, a materialshowing a linear relation between the pressure drop ΔP and the flow rateup to 0.3 kgf/cm² is referred to as a “hard material”.

Example 1

First, 22 ml of water, 31 ml of a 4N NaOH aqueous solution, and 32 ml ofepichlorohydrin were added to 100 ml of porous cellulose beads having anaverage particle diameter of about 450 μm and a molecular weightexclusion limit of 5×10⁷ for globular proteins, followed by reaction at40° C. for 2 hours under stirring. After the reaction, the beads weresufficiently washed with water to prepare epoxidized cellulose beads.The amount of the epoxy groups of the epoxidized cellulose beads was16.4 μmol/ml (wet volume).

On the other hand, 7.5 g of dextran sulfate (sulfur content: about 18%,molecular weight: about 4000) was dissolved in 25 ml of water to preparean aqueous dextran sulfate solution. Then, 50 ml of the epoxidizedcellulose beads wetted with water was added to the aqueous dextransulfate solution, and the resultant mixture was adjusted to alkali witha NaOH aqueous solution, followed by reaction at 45° C. for 1.5 hours.After the reaction, the beads were sufficiently washed with water andbrine, and a solution prepared by dissolving 0.77 g of L-tryptophan in50 ml of a diluted NaOH aqueous solution was added to the beads,followed by reaction at 50° C. for 8 hours. Then, the beads weresufficiently washed with water and brine to prepare cellulose beads (A)with immobilized dextran sulfate and tryptophan.

Beads A were charged in an acrylic column (volume 2.7 ml) having aninner diameter of 10 mm and a length of 34 mm and comprisingpolyethylene terephthalate meshes provided at both ends and each havingan opening of 150 μm. Then, 40 ml of the blood of a healthy adult, whichwas anticoagulated by adding 5 units of heparin per milliliter of blood,was circulated through the column at a flow rate of 6.5 ml/min for 2hours. Table 1 shows the numbers of the blood cells in the pooled bloodbefore and after the circulation for 2 hours. All blood cells showedexcellent passing property. Table 2 shows the concentrations ofLDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 2, LDL-cholesterolis decreased from 116 mg/dl to 78 mg/dl, and fibrinogen is decreasedfrom 132 mg/dl to 93 mg/dl, but HDL-cholesterol is slightly decreasedfrom 66 mg/dl to 62 mg/dl.

The amount of the immobilized tryptophan on beads A was determined fromthe nitrogen content of the adsorbent. Namely, 1 ml of beads A wassufficiently washed with water, dried under reduced pressure at 60° C.for 6 hours or more, and then quantitatively analyzed by a totalnitrogen microanalyzer. As a result, the amount of the immobilizedtryptophan on beads A was 7.8 μmol/ml.

The amount of the immobilized dextran sulfate of beads A was measured byutilizing the affinity of dextran sulfate for toluidine blue. Namely,about 100 ml of a toluidine blue (Basic blue 17 (Tokyo Kasei Kogyo Co.,Ltd.) aqueous solution adjusted to about 90 mg/l was added to 3 ml ofbeads A, and the resultant mixture was stirred for 10 minutes andallowed to stand. Then, the amount of the toluidine blue in thesupernatant was determined by absorbance at 630 nm, and a decrease inamount of the toluidine blue was determined as the amount of theimmobilized dextran sulfate. As a result, the amount of the immobilizeddextran on beads A was 0.16 μmol/ml, and the ratio TR/PA was 48.6.

Example 2

First, 4 ml of water, 32 ml of a 4N NaOH aqueous solution, and 29 ml ofepichlorohydrin were added 100 ml of the same cellulose beads as inEXAMPLE 1, followed by reaction at 40° C. for 2 hours under stirring.After the reaction, the beads were sufficiently washed with water toprepare epoxidized cellulose beads. The amount of the epoxy groups ofthe epoxidized cellulose beads was 19.9 μmol/ml (wet volume).

On the other hand, 7.5 g of the same dextran sulfate as in EXAMPLE 1 wasdissolved in 25 ml of water to prepare an aqueous dextran sulfatesolution. Then, 50 ml of the epoxidized cellulose beads wetted withwater was added to the aqueous dextran sulfate solution, and theresultant mixture was adjusted to alkali with a NaOH aqueous solution,followed by reaction at 45° C. for 3 hours. After the reaction, thebeads were sufficiently washed with water and brine, and a solutionprepared by dissolving 0.77 g of L-tryptophan in 50 ml of a diluted NaOHaqueous solution was added to the beads, followed by reaction at 55° C.for 6 hours. Then, the beads were sufficiently washed with water andbrine to prepare cellulose beads (B) with immobilized dextran sulfateand tryptophan. The amount of the immobilized tryptophan on beads B was7.8 μmol/ml, the amount of the immobilized dextran sulfate on beads Bwas 0.23 μmol/ml, and the TR/PA ratio was 33.8.

Beads B were charged in a column, and 40 ml of the blood of a healthyadult was circulated through the column for 2 hours by the same methodas in EXAMPLE 1. Table 1 shows the numbers of the blood cells in thepooled blood before and after the circulation. All blood cells showedexcellent passing property. Table 2 shows the concentrations ofLDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 2, LDL-cholesterolis decreased from 91 mg/dl to 51 mg/dl, and fibrinogen is decreased from220 mg/dl to 143 mg/dl, but HDL-cholesterol is slightly decreased from42 mg/dl to 41 mg/dl.

Example 3

First, 55 ml of water, 15 ml of a 4N NaOH aqueous solution, and 14 ml ofepichlorohydrin were added 100 ml of the same cellulose beads as inEXAMPLE 1, followed by reaction at 40° C. for 2 hours under stirring.After the reaction, the beads were sufficiently washed with water toprepare epoxidized cellulose beads. The amount of the epoxy groups ofthe epoxidized cellulose beads was 8.8 μmol/ml (wet volume).

On the other hand, 19.8 g of the same dextran sulfate as in EXAMPLE 1was dissolved in 25 ml of water to prepare an aqueous dextran sulfatesolution. Then, 50 ml of the epoxidized cellulose beads wetted withwater were added to the aqueous dextran sulfate solution, and theresultant mixture was adjusted to alkali with a NaOH aqueous solution,followed by reaction at 45° C. for 6 hours. After the reaction, thebeads were sufficiently washed with water and brine, and a solutionprepared by dissolving 0.77 g of L-tryptophan in 50 ml of a diluted NaOHaqueous solution was added to the beads, followed by reaction at 50° C.for 8 hours. Then, the beads were sufficiently washed with water andbrine to prepare cellulose beads (C) with immobilized dextran sulfateand tryptophan. The amount of the immobilized tryptophan on beads C was4.0 μmol/ml, the amount of the immobilized dextran sulfate on beads Cwas 0.32 μmol/ml, and the TR/PA ratio was 12.5.

Beads C were charged in a column, and 40 ml of the blood of a healthyadult was circulated through the column for 2 hours by the same methodas in EXAMPLE 1. Table 1 shows the numbers of the blood cells in thepooled blood before and after the circulation. All blood cells showedexcellent passing property. Table 2 shows the concentrations ofLDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 2, LDL-cholesterolis decreased from 163 mg/dl to 101 mg/dl, and fibrinogen is decreasedfrom 215 mg/dl to 167 mg/dl, but HDL-cholesterol is slightly decreasedfrom 60 mg/dl to 56 mg/dl.

Comparative Example 1

Cellulose beads (D) with immobilized dextran sulfate and tryptophan wereprepared by the same method as in EXAMPLE 3 except that the reactiontime of dextran sulfate was changed from 6 hours to 0.5 hour, and theamount of dextran sulfate was changed from 19.8 g to 7.5 g. The amountof the immobilized tryptophan on beads D was 5.7 μmol/ml, the amount ofthe immobilized dextran sulfate on beads D was 0.08 μmol/ml, and theTR/PA ratio was 70.9.

Beads D were charged in a column, and 40 ml of the blood of a healthyadult was circulated through the column for 2 hours by the same methodas in EXAMPLE 1. Table 1 shows the numbers of the blood cells in thepooled blood before and after the circulation. Although erythrocytesshowed excellent passing property, leukocytes and platelets aredecreased to 66% and 63%, respectively, after the circulation, and thusshowed slightly low passing property. Table 2 shows the concentrationsof LDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 2, fibrinogen isdecreased from 189 mg/dl to 127 mg/dl, but LDL-cholesterol is slightlydecreased from 86 mg/dl to 62 mg/dl, and HDL-cholesterol is slightlydecreased from 66 mg/dl to 63 mg/dl.

Comparative Example 2

First, 14 ml of water, 24 ml of a 4N NaOH aqueous solution, and 29 ml ofepichlorohydrin were added 100 ml of the same cellulose beads as inEXAMPLE 1, followed by reaction at 40° C. for 2 hours under stirring.After the reaction, the beads were sufficiently washed with water toprepare epoxidized cellulose beads. The amount of the epoxy groups ofthe epoxidized cellulose beads was 14.7 μmol/ml (wet volume).

Then, a solution prepared by dissolving 0.77 g of L-tryptophan in 50 mlof a diluted NaOH aqueous solution was added to 50 ml of the epoxidizedcellulose beads, followed by reaction at 55° C. for 6 hours. Then, thebeads were sufficiently washed with water and brine to prepare cellulosebeads (E) with immobilized tryptophan. The amount of the immobilizedtryptophan on beads E was 8.2 μmol/ml.

Beads E were charged in a column, and 40 ml of the blood of a healthyadult was circulated through the column for 2 hours by the same methodas in EXAMPLE 1. Table 1 shows the numbers of the blood cells in thepooled blood before and after the circulation. Although erythrocytes andleukocytes showed excellent passing property, platelets are decreased to69% after the circulation and thus showed slightly low passing property.Table 2 shows the concentrations of LDL-cholesterol, fibrinogen, andHDL-cholesterol in the pooled blood before and after the circulation. Asshown in Table 2, fibrinogen is decreased from 132 mg/dl to 77 mg/dl,but LDL-cholesterol is slightly decreased from 116 mg/dl to 85 mg/dl,and HDL-cholesterol is slightly decreased from 66 mg/dl to 61 mg/dl.

Example 4

First, 42 ml of water, 100 ml of a 2N NaOH aqueous solution, and 17 mlof epichlorohydrin were added 100 ml of porous cellulose beads having anaverage particle diameter of about 410 μm and a molecular weightexclusion limit of 5×10⁷ for globular proteins, followed by reaction at40° C. for 2 hours. After the reaction, the beads were sufficientlywashed with water to prepare epoxidized cellulose beads. The amount ofthe epoxy groups of the epoxidized cellulose beads was 16.5 μmol/ml (wetvolume).

On the other hand, 23.3 g of the same dextran sulfate as in EXAMPLE 1was dissolved in 39 ml of water to prepare an aqueous dextran sulfatesolution. Then, 50 ml of the epoxidized cellulose beads wetted withwater was added to the aqueous dextran sulfate solution, and theresultant mixture was adjusted to alkali with a NaOH aqueous solution,followed by reaction at 45° C. for 6 hours. After the reaction, thebeads were sufficiently washed with water and brine, and a solutionprepared by dissolving 0.93 g of L-tryptophan in 50 ml of water byheating was added to the beads. After the resultant mixture was adjustedto alkali with a NaOH aqueous solution, reaction was performed at 50° C.for 8 hours. Then, the beads were sufficiently washed with water andbrine to prepare cellulose beads (F) with immobilized dextran sulfateand tryptophan. The amount of the immobilized tryptophan on beads F was7.8 μmol/ml, the amount of the immobilized dextran sulfate on beads Fwas 0.17 μmol/ml, and the TR/PA ratio was 45.9.

Beads F were charged in an acrylic column (volume 3.5 ml) having aninner diameter of 10 mm and a length of 45 mm and comprisingpolyethylene terephthalate meshes provided at both ends and each havingan opening of 50 μm. Then, 43 ml of the blood of a healthy adult, whichwas anticoagulated by adding 5 units of heparin per milliliter of blood,was circulated through the column at a flow rate of 2.1 ml/min for 2hours. Table 3 shows the numbers of the blood cells in the pooled bloodbefore and after the circulation for 2 hours. All blood cells showedexcellent passing property. Table 4 shows the concentrations ofLDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 4, LDL-cholesterolis decreased from 141 mg/dl to 94 mg/dl, and fibrinogen is decreasedfrom 234 mg/dl to 146 mg/dl, but HDL-cholesterol is slightly decreasedfrom 49 mg/dl to 45 mg/dl.

Comparative Example 3

First, 42 ml of water, 50 ml of a 2N NaOH aqueous solution, and 17 ml ofepichlorohydrin were added 100 ml of the same cellulose beads as inEXAMPLE 4, followed by reaction at 40° C. for 2 hours under stirring.After the reaction, the beads were sufficiently washed with water toprepare epoxidized cellulose beads. The amount of the epoxy groups ofthe epoxidized cellulose beads was 12.4 μmol/ml (wet volume).

Then, 23.3 g of the same dextran sulfate in EXAMPLE 1 was dissolved in39 ml of water to prepare an aqueous dextran sulfate solution, and 50 mlof the epoxidized cellulose beads wetted with water was added to theaqueous dextran sulfate solution. After the resultant mixture wasadjusted to alkali with a NaOH aqueous solution, reaction was performedat 45° C. for 20 hours. Then, the beads were sufficiently washed withwater and brine to prepare cellulose beads (G) with immobilized dextransulfate. The amount of the immobilized dextran sulfate on beads G was0.6 μmol/ml.

Beads G were charged in a column, and 43 ml of the blood of a healthyadult was circulated through the column for 2 hours by the same methodas in EXAMPLE 4. Table 3 shows the numbers of the blood cells in thepooled blood before and after the circulation. Although erythrocytesshowed excellent passing property, leukocytes and platelets aredecreased to 66% and 63%, respectively, after the circulation and thusshowed slightly low passing property. Table 4 shows the concentrationsof LDL-cholesterol, fibrinogen, and HDL-cholesterol in the pooled bloodbefore and after the circulation. As shown in Table 4, fibrinogen isdecreased from 141 mg/dl to 89 mg/dl, but LDL-cholesterol is slightlydecreased from 234 mg/dl to 198 mg/dl, and HDL-cholesterol is slightlydecreased from 49 mg/dl to 46 mg/dl.

Example 5

First, 1.0 ml of cellulose beads (B) with immobilized dextran sulfateand tryptophan prepared in EXAMPLE 2 was measured, and 10 ml of theplasma of a healthy person was added to the beads, followed byincubation at 37° C. for 4 hours. After incubation, plasma was separatedfrom the beads, and the concentrations of LDL-cholesterol, fibrinogen,albumin, IgG, and HDL-cholesterol of the plasma were measured. Theresults are shown in Table 5. As shown in Table 5, LDL-cholesterol isdecreased from 115 mg/dl to 81 mg/dl, and fibrinogen is decreased from244 mg/dl to 186 mg/dl, but albumin is slightly decreased from 4.5 g/dlto 4.3 g/dl, IgG is slightly decreased from,1203 mg/dl to 1133 mg/dl,and HDL-cholesterol is slightly decreased from 62 mg/dl to 59 mg/dl.

Example 6

First, 1.0 ml of cellulose beads (F) with immobilized dextran sulfateand tryptophan prepared in EXAMPLE 4 was measured, and 10 ml of theplasma of a healthy adult was added to the beads, followed by incubationat 37° C. for 4 hours. After incubation, plasma was separated from thebeads, and the concentrations of LDL-cholesterol, fibrinogen, albumin,IgG, and HDL-cholesterol of the plasma were measured. The results areshown in Table 5. As shown in Table 5, LDL-cholesterol is decreased from87 mg/dl to 62 mg/dl, and fibrinogen is decreased from 260 mg/dl to 190mg/dl, but albumin is slightly decreased from 4.7 g/dl to 4.5 g/dl, IgGis slightly decreased from 927 mg/dl to 876 mg/dl, and HDL-cholesterolis slightly decreased from 55 mg/dl to 54 mg/dl. TABLE 1 Amount ofNumber of leukocytes Average immobilized Amount of [×10²/μl] particledextran immobilized TR/PA Before After diameter sulfate tryptophan ratioblood blood Ratio* Adsorbent [μm] [μmol/ml] [μmol/ml] [—] perfusionperfusion [%] Example 1 A 450 0.16 7.8 48.6 40 34 85 Example 2 B 4500.23 7.8 33.8 55 48 87 Example 3 C 450 0.32 4.0 12.5 59 52 88 Comp. D450 0.08 5.7 70.9 47 31 66 Example 1 Comp. E 450 0 8.2 — 40 35 88Example 2 Number of platelets [×10⁴/μl] Number of erythrocytes BeforeAfter [×10⁴/μl] blood blood Ratio* Before After perfusion perfusion [%]blood perfusion blood perfusion Ratio* [%] Example 1 18.1 13.6 75 493499 101 Example 2 16.8 12.4 74 504 510 101 Example 3 22.7 17.9 79 498500 100 Comp. 19.0 12.0 63 441 444 101 Example 1 Comp. 18.1 12.4 69 493503 102 Example 2Ratio*: After blood perfusion/before blood perfusion × 100

TABLE 2 Amount of Average immobilized Amount of LDL-cholesterol particledextran immobilized TR/PA Rate of Fibrinogen diameter sulfate tryptophanratio [mg/dl] Decrease [mg/dl] Rate of Adsorbent [μm] [μmol/ml][μmol/ml] [—] Before*) After*) [%] Before*) After*) Decrease [%] Example1 A 450 0.16 7.8 48.6 116 78 33 132 93 30 Example 2 B 450 0.23 7.8 33.891 51 44 220 143 35 Example 3 C 450 0.32 4.0 12.5 163 101 38 215 167 22Comp. D 450 0.08 5.7 70.9 86 62 28 189 127 33 Example 1 Comp. E 450 08.2 — 116 85 27 132 77 42 Example 2 Amount of adsorption HDL-cholesterolLDL- HDL- [mg/dl] Rate of cholesterol Fibrinogen cholesterol Before*)After*) decrease [%] [mg/mL-gel] [mg/mL-gel] [mg/mL-gel] Example 1 66 626 3.1 3.2 0.2 Example 2 42 41 2 3.2 6.2 0.1 Example 3 60 56 7 5.0 3.90.3 Comp. 66 63 5 2.0 5.3 0.3 Example 1 Comp. 66 61 8 2.6 4.6 0.4Example 2Before: Before blood perfusionAfter: After blood perfusion

TABLE 3 Amount of Number of leukocytes Average immobilized Amount of[×10²/μl] particle dextran immobilized TR/PA Before After diametersulfate tryptophan ratio blood blood Ratio* Adsorbent [μm] [μmol/ml][μmol/ml] [—] perfusion perfusion [%] Example 4 F 410 0.17 7.8 45.9 5952 88 Comp. G 410 0.6 0 0 47 31 66 Example 3 Number of platelets[×10⁴/μl] Number of erythrocytes Before After [×10⁴/μl] blood bloodRatio* Before After perfusion perfusion [%] blood perfusion bloodperfusion Ratio* [%] Example 4 22.7 17.9 79 498 500 100 Comp. 19.0 12.063 441 444 101 Example 3Ratio*: After blood perfusion/before blood perfusion × 100

TABLE 4 Amount of Average immobilized Amount of LDL-cholesterol particledextran immobilized TR/PA Rate of Fibrinogen diameter sulfate tryptophanratio [mg/dl] Decrease [mg/dl] Rate of Adsorbent [μm] [μmol/ml][μmol/ml] [—] Before*) After*) [%] Before*) After*) Decrease [%] Example4 F 410 0.17 7.8 45.9 141 94 33 234 146 38 Comp. G 410 0.6 0 0 141 89 37234 198 15 Example 3 Amount of adsorption HDL-cholesterol LDL- HDL-[mg/dl] Rate of cholesterol Fibrinogen cholesterol Before*) After*)decrease [%] [mg/mL-gel] [mg/mL-gel] [mg/mL-gel] Example 4 49 45 8 3.25.9 0.3 Comp. 49 46 6 3.5 2.4 0.2 Example 3Before: Before blood perfusionAfter: After blood perfusion

TABLE 5 Measurement items Average LDL-cholesterol Fibrinogen Albuminparticle [mg/dl] Rate of [mg/dl] Rate of [g/dl] Rate of diameter BeforeAfter Decrease Before After Decrease Before After Decrease Absorbent[μm] adsorption adsorption [%] adsorption adsorption [%] adsorptionadsorption [%] Example 5 B 450 115 81 30 244 186 24 4.5 4.3 4 Example 6F 410 87 62 29 260 190 27 4.7 4.5 4 IgG HDL-cholesterol [mg/dl] Rate of[mg/dl] Rate of Measurement Before After Decrease Before After Decreaseitems adsorption adsorption [%] adsorption adsorption [%] Example 5 12031133 6 62 59 5 Example 6 927 876 6 55 54 2

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing an example of anadsorber of the present invention.

Reference numerals each denote the following:

1 body fluid inlet

2 body fluid outlet

3 adsorbent for low-density lipoproteins and fibrinogen

4, 5 mesh (means for preventing adsorbent outflow)

6 column

7 adsorber for low-density lipoproteins and fibrinogen

FIG. 2 is a graph showing the relation between the flow rate andpressure drop in the use of three types of gels.

INDUSTRIAL APPLICABILITY

According to the present invention, low-density lipoproteins andfibrinogen can be efficiently adsorbed directly from a body fluid,particularly whole blood, to decrease the concentrations of thesecomponents in the body fluid with minimizing losses of useful substancessuch as HDL and albumin. The present invention is particularly effectiveas a method for decreasing the concentrations of low-densitylipoproteins and fibrinogen in the blood of a patient witharteriosclerosis, particularly arteriosclerosis obliterans.

1. An adsorbent capable of whole blood treatment for adsorbinglow-density lipoproteins and fibrinogen, the adsorbent comprising atryptophan derivative and a polyanionic compound which are immobilizedon a water-insoluble porous carrier, wherein the amount of theimmobilized polyanionic compound is 0.10 μmol to 1.5 μmol per milliliterof wet volume of the adsorbent, and the molar ratio of the amount of theimmobilized tryptophan derivative to the amount of the immobilizedpolyanionic compound is 1 to
 70. 2. The adsorbent capable of whole bloodtreatment for adsorbing low-density lipoproteins and fibrinogenaccording to claim 1, wherein the polyanionic compound is dextransulfate.
 3. The adsorbent capable of whole blood treatment for adsorbinglow-density lipoproteins and fibrinogen according to claim 1, whereinthe tryptophan derivative is tryptophan.
 4. The adsorbent capable ofwhole blood treatment for adsorbing low-density lipoproteins andfibrinogen according to claim 1, wherein the water-insoluble porouscarrier is a cellulose carrier.
 5. The adsorbent capable of whole bloodtreatment for adsorbing low-density lipoproteins and fibrinogenaccording to claim 1, wherein the water-insoluble porous carrier has amolecular weight exclusion limit of 5×10⁵ to 1×10⁸ for globularproteins.
 6. A method for adsorbing low-density lipoproteins andfibrinogen from a body fluid, the method comprising bringing theadsorbent capable of whole blood treatment for adsorbing low-densitylipoproteins and fibrinogen according to claim 1 into contact with abody fluid containing low-density lipoproteins and fibrinogen.
 7. Anadsorber capable of whole blood treatment for absorbing low-densitylipoproteins and fibrinogen, the adsorber comprising a container havinga fluid inlet, a fluid cutlet, and means for preventing an outflow of anadsorbent to the outside, wherein the container is filled with theadsorbent capable of whole blood treatment for adsorbing low-densitylipoproteins and fibrinogen according to claim
 1. 8. The adsorbercapable of whole blood treatment for absorbing low-density lipoproteinsand fibrinogen according to claim 7, wherein the capacity of theadsorber is 100 ml to 400 ml.
 9. The adsorbent capable of whole bloodtreatment for adsorbing low-density lipoproteins and fibrinogenaccording to claim 2, wherein the tryptophan derivative is tryptophan.10. The adsorbent capable of whole blood treatment for adsorbinglow-density lipoproteins and fibrinogen according to claim 2, whereinthe water-insoluble porous carrier is a cellulose carrier.
 11. Theadsorbent capable of whole blood treatment for adsorbing low-densitylipoproteins and fibrinogen according to claim 3, wherein thewater-insoluble porous carrier is a cellulose carrier.
 12. The adsorbentcapable of whole blood treatment for adsorbing low-density lipoproteinsand fibrinogen according to claim 9, wherein the water-insoluble porouscarrier is a cellulose carrier.
 13. The adsorbent capable of whole bloodtreatment for adsorbing low-density lipoproteins and fibrinogenaccording to claim 2, wherein the water-insoluble porous carrier has amolecular weight exclusion limit of 5×10⁵ to 1×10⁸ for globularproteins.
 14. The adsorbent capable of whole blood treatment foradsorbing low-density lipoproteins and fibrinogen according to claim 3,wherein the water-insoluble porous carrier has a molecular weightexclusion limit of 5×10⁵ to 1×10⁸ for globular proteins.
 15. Theadsorbent capable of whole blood treatment for adsorbing low-densitylipoproteins and fibrinogen according to claim 4, wherein thewater-insoluble porous carrier has a molecular weight exclusion limit of5×10⁵ to 1×10⁸ for globular proteins.
 16. A method for adsorbinglow-density lipoproteins and fibrinogen from a body fluid, the methodcomprising bringing the adsorbent capable of whole blood treatment foradsorbing low-density lipoproteins and fibrinogen according to claim 5into contact with a body fluid containing low-density lipoproteins andfibrinogen.
 17. An adsorber capable of whole blood treatment forabsorbing low-density lipoproteins and fibrinogen, the adsorbercomprising a container having a fluid inlet, a fluid cutlet, and meansfor preventing an outflow of an adsorbent to the outside, wherein thecontainer is filled with the adsorbent capable of whole blood treatmentfor adsorbing low-density lipoproteins and fibrinogen according to claim5.
 18. An adsorber capable of whole blood treatment for absorbinglow-density lipoproteins and fibrinogen, the adsorber comprising acontainer having a fluid inlet, a fluid cutlet, and means for preventingan outflow of an adsorbent to the outside, wherein the container isfilled with the adsorbent capable of whole blood treatment for adsorbinglow-density lipoproteins and fibrinogen according to claim 6.